BRUSSELS: British Prime Minister David Cameron and 27 other European Union leaders headed back into talks on Friday after marathon overnight negotiations failed to cement a new deal for Britain in the bloc.

Talks ran overnight as Cameron pressed his demands for EU reforms, with several of his EU peers unhappy that he should get a special deal when they have grievances of their own.

Arriving at the EU headquarters building in Brussels, Cameron said: “We’ve made some progress, but there’s still no deal,” Cameron said as he returned for talks just hours after wrapping up meetings at 5:30 a.m.

“We’re going to get back in there. We’re going to do some more work and I’ll do everything I can.”

Cameron has repeatedly warned that if he fails to get a deal, he will walk away from Brussels with all options open, including the possibility that Britain becomes the first country to leave the EU in its more than 60-year history.

He has four key demands — the right to curb migrant social welfare benefits, safeguards for non-euro countries against greater eurozone integration, an opt-out from ever “closer union” and measures to boost the EU’s competitive standing.

Some member states, most notably Germany, agree with many of his reforms but others such as France and Belgium baulk at Britain having any sort of veto over those who want to press ahead with increased EU convergence.

EU president Donald Tusk warned in the early hours Friday that there was “a lot to do” to reach an accord.